Raman Detection Using Synchronous SPAD Control
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Solution Overview
Problem
Current Raman radiation measurement systems face challenges due to low duty cycle, high-energy requirements, and significant background noise, making them impractical and limited to laboratory use.
Innovation Solution
An apparatus and method that electrically control detecting elements to perform Raman radiation measurement without additional gating devices, allowing for higher repetition rates and reduced background noise by using SPAD-arrays and a controller to switch detecting elements on and off synchronously with optical pulses, effectively filtering out background noise and fluorescence.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a Kerr-gate is used to block excitation radiation and suppress background noise, then measurement precision is improved, but device complexity increases and duty cycle becomes too low for practical use
Solution Approach 1:
The patent extracts and removes the complex Kerr-gate component from the system. Instead of using an optically controlled Kerr-gate to suppress background noise, the invention uses simple optical filters (notch filters and long-pass filters) combined with direct detection, eliminating the need for complex gating mechanisms while maintaining measurement precision.
Solution Approach 2:
The patent replaces expensive, complex Kerr-gate equipment with simpler, more affordable optical filters and detectors. This substitution uses inexpensive components that can be easily replaced or adjusted, making the system more practical for field use rather than requiring expensive laboratory equipment.
2Measurement precision
If an image intensifier is used to amplify Raman signal, then measurement precision is improved, but background noise increases due to thermal and electron multiplication noise
Solution Approach 1:
The patent removes the image intensifier component from the system entirely. Instead of amplifying the signal through an intensifier that introduces thermal and electron multiplication noise, the invention uses direct detection with sensitive detectors combined with optical filtering to achieve high signal-to-noise ratio without the harmful noise sources.
Solution Approach 2:
The patent introduces optical filters as intermediary components between the sample and detector. These filters (notch filters and long-pass filters) selectively transmit Raman signals while blocking excitation radiation and fluorescence, acting as a clean intermediary that enhances signal quality without introducing the noise problems associated with image intensifiers.
3Reliability
If high-energy optical pulses are used to drive Kerr-gate, then gating performance is improved, but energy available for measuring object is drastically limited
Solution Approach 1:
The patent extracts and removes the Kerr-gate component that requires high-energy optical pulses for operation. By eliminating this component, the system no longer needs to divert significant energy to drive the gating mechanism, allowing much more energy to be used for actual Raman measurement of the object.
Solution Approach 2:
The patent replaces the optically controlled Kerr-gate system with a passive optical filtering system. This substitution eliminates the need for high-energy optical control pulses, as the filtering is achieved through passive optical components rather than active optically-controlled switching, thereby conserving energy for measurement purposes.
4Difficulty of detecting and measuring
If Kerr-gate or image intensifier is used for Raman measurement, then detection capability is improved, but system becomes complicated, expensive and large for laboratory use only
Solution Approach 1:
The patent extracts and removes the bulky, expensive components (Kerr-gate and image intensifier) from the system. By using simpler optical filters and direct detection, the system achieves comparable or sufficient detection capability with much reduced size, cost, and complexity, enabling field deployment rather than laboratory-only use.
Solution Approach 2:
The patent replaces expensive, fragile laboratory equipment with simpler, more robust, and affordable components. The optical filters and detectors used are more durable and less expensive than Kerr-gates or image intensifiers, making the system suitable for field experiments and industrial applications where equipment may be subject to harsher conditions.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enables on-line Raman radiation measurement with improved signal-to-noise ratio and increased measurement speed, reducing the system's complexity and cost, making it suitable for field experiments and industrial applications.
Implementation Method 1
a plurality of detecting elements to receive different bands of spectrum of the Raman radiation formed in response to at least one optical pulse
Implementation Method 2
a disperser to disperse different wavelengths i.e. photons of different energies in different directions
Data Source
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AI summary
An apparatus comprises a plurality of detecting elements and a summer. Each detecting element receives and detects different bands of spectrum of Raman radiation formed in response to at least one optical excitation pulse directed to the object. The detecting elements and/or the summer receives a command to enable registration of detections in the detecting elements and a command to disable the registration during or after the Raman radiation. The summer registers separately the detections of the Raman radiation in at least two detecting elements for presenting data on the object on the basis of the detections.